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<FONT color="green">001</FONT>    // Copyright 2006-2008 Regents of the University of California.  May be used <a name="line.1"></a>
<FONT color="green">002</FONT>    // under the terms of the revised BSD license.  See LICENSING for details.<a name="line.2"></a>
<FONT color="green">003</FONT>    package org.joe_e.file;<a name="line.3"></a>
<FONT color="green">004</FONT>    <a name="line.4"></a>
<FONT color="green">005</FONT>    import java.io.File;<a name="line.5"></a>
<FONT color="green">006</FONT>    import java.io.FileInputStream;<a name="line.6"></a>
<FONT color="green">007</FONT>    import java.io.FileNotFoundException;<a name="line.7"></a>
<FONT color="green">008</FONT>    import java.io.FileOutputStream;<a name="line.8"></a>
<FONT color="green">009</FONT>    import java.io.IOException;<a name="line.9"></a>
<FONT color="green">010</FONT>    import java.io.InputStream;<a name="line.10"></a>
<FONT color="green">011</FONT>    import java.io.OutputStream;<a name="line.11"></a>
<FONT color="green">012</FONT>    import java.util.Arrays;<a name="line.12"></a>
<FONT color="green">013</FONT>    import java.util.Comparator;<a name="line.13"></a>
<FONT color="green">014</FONT>    <a name="line.14"></a>
<FONT color="green">015</FONT>    import org.joe_e.array.ConstArray;<a name="line.15"></a>
<FONT color="green">016</FONT>    <a name="line.16"></a>
<FONT color="green">017</FONT>    /**<a name="line.17"></a>
<FONT color="green">018</FONT>     * {@link File} construction.  This provides a capability-safe API for access to<a name="line.18"></a>
<FONT color="green">019</FONT>     * files.  A File object grants read and write access to a file or directory.<a name="line.19"></a>
<FONT color="green">020</FONT>     * Due to limitations in Java, all file references are to textual file names, not<a name="line.20"></a>
<FONT color="green">021</FONT>     * file descriptors.  Multiple operations on a File may thus apply to different<a name="line.21"></a>
<FONT color="green">022</FONT>     * incarnations of the file.<a name="line.22"></a>
<FONT color="green">023</FONT>     */<a name="line.23"></a>
<FONT color="green">024</FONT>    public final class Filesystem {<a name="line.24"></a>
<FONT color="green">025</FONT>        <a name="line.25"></a>
<FONT color="green">026</FONT>        private Filesystem() {}<a name="line.26"></a>
<FONT color="green">027</FONT>        <a name="line.27"></a>
<FONT color="green">028</FONT>        /*<a name="line.28"></a>
<FONT color="green">029</FONT>         * The safety of this API relies on all File constructors being tamed away. <a name="line.29"></a>
<FONT color="green">030</FONT>         */<a name="line.30"></a>
<FONT color="green">031</FONT>        <a name="line.31"></a>
<FONT color="green">032</FONT>        /**<a name="line.32"></a>
<FONT color="green">033</FONT>         * Produce a File capability for a file contained in a folder.  The returned<a name="line.33"></a>
<FONT color="green">034</FONT>         * object is just a handle; the underlying file may not yet exist.<a name="line.34"></a>
<FONT color="green">035</FONT>         * @param folder    containing folder<a name="line.35"></a>
<FONT color="green">036</FONT>         * @param child     a single filename component, not a relative path<a name="line.36"></a>
<FONT color="green">037</FONT>         * @return a capability for the requested file<a name="line.37"></a>
<FONT color="green">038</FONT>         * @throws IllegalArgumentException if &lt;code&gt;folder&lt;/code&gt; is null or<a name="line.38"></a>
<FONT color="green">039</FONT>         *     the empty path<a name="line.39"></a>
<FONT color="green">040</FONT>         */<a name="line.40"></a>
<FONT color="green">041</FONT>        static public File file(final File folder, final String child) <a name="line.41"></a>
<FONT color="green">042</FONT>                                           throws InvalidFilenameException {<a name="line.42"></a>
<FONT color="green">043</FONT>            // With Java's File(File, String) constructor, either of these can give<a name="line.43"></a>
<FONT color="green">044</FONT>            // access to all files on system; null is ambiently available.<a name="line.44"></a>
<FONT color="green">045</FONT>            if (folder == null || folder.getPath().equals("")) {<a name="line.45"></a>
<FONT color="green">046</FONT>                throw new IllegalArgumentException();<a name="line.46"></a>
<FONT color="green">047</FONT>            }<a name="line.47"></a>
<FONT color="green">048</FONT>            checkName(child);<a name="line.48"></a>
<FONT color="green">049</FONT>            return new File(folder, child);<a name="line.49"></a>
<FONT color="green">050</FONT>        }<a name="line.50"></a>
<FONT color="green">051</FONT>    <a name="line.51"></a>
<FONT color="green">052</FONT>        /**<a name="line.52"></a>
<FONT color="green">053</FONT>         * Vets a filename.  Checks that the argument would be interpreted as a<a name="line.53"></a>
<FONT color="green">054</FONT>         * file name rather than as a path or relative directory specifier<a name="line.54"></a>
<FONT color="green">055</FONT>         * @param name a single filename component, not a relative path<a name="line.55"></a>
<FONT color="green">056</FONT>         * @throws InvalidFilenameException &lt;code&gt;name&lt;/code&gt; is rejected\<a name="line.56"></a>
<FONT color="green">057</FONT>         */<a name="line.57"></a>
<FONT color="green">058</FONT>        static public void checkName(final String name) <a name="line.58"></a>
<FONT color="green">059</FONT>                                           throws InvalidFilenameException {<a name="line.59"></a>
<FONT color="green">060</FONT>            // Check for path operation names.<a name="line.60"></a>
<FONT color="green">061</FONT>            if (name.equals("") || name.equals(".") || name.equals("..")) {<a name="line.61"></a>
<FONT color="green">062</FONT>                throw new InvalidFilenameException();<a name="line.62"></a>
<FONT color="green">063</FONT>            }<a name="line.63"></a>
<FONT color="green">064</FONT>    <a name="line.64"></a>
<FONT color="green">065</FONT>            // Check for path separator char.<a name="line.65"></a>
<FONT color="green">066</FONT>            if (name.indexOf(File.separatorChar) != -1) {<a name="line.66"></a>
<FONT color="green">067</FONT>                throw new InvalidFilenameException();<a name="line.67"></a>
<FONT color="green">068</FONT>            }      <a name="line.68"></a>
<FONT color="green">069</FONT>            // '/' works as a separator on Windows, even though it isn't the <a name="line.69"></a>
<FONT color="green">070</FONT>            // platform separator character<a name="line.70"></a>
<FONT color="green">071</FONT>            if ('/' != File.separatorChar &amp;&amp; name.indexOf('/') != -1) {<a name="line.71"></a>
<FONT color="green">072</FONT>                throw new InvalidFilenameException();<a name="line.72"></a>
<FONT color="green">073</FONT>            }<a name="line.73"></a>
<FONT color="green">074</FONT>        }<a name="line.74"></a>
<FONT color="green">075</FONT>        <a name="line.75"></a>
<FONT color="green">076</FONT>        /**<a name="line.76"></a>
<FONT color="green">077</FONT>         * List the contents of a directory.<a name="line.77"></a>
<FONT color="green">078</FONT>         * @param dir   directory to list<a name="line.78"></a>
<FONT color="green">079</FONT>         * @return directory entries, sorted alphabetically<a name="line.79"></a>
<FONT color="green">080</FONT>         * @throws IOException &lt;code&gt;dir&lt;/code&gt; is not a directory, or an I/O error<a name="line.80"></a>
<FONT color="green">081</FONT>         */<a name="line.81"></a>
<FONT color="green">082</FONT>        static public ConstArray&lt;File&gt; list(final File dir) throws IOException {<a name="line.82"></a>
<FONT color="green">083</FONT>            final File[] contents = dir.listFiles();<a name="line.83"></a>
<FONT color="green">084</FONT>            if (contents == null) { <a name="line.84"></a>
<FONT color="green">085</FONT>                throw new IOException();<a name="line.85"></a>
<FONT color="green">086</FONT>            }<a name="line.86"></a>
<FONT color="green">087</FONT>            Arrays.sort(contents, new Comparator&lt;File&gt;() {<a name="line.87"></a>
<FONT color="green">088</FONT>                public int compare(final File a, final File b) {<a name="line.88"></a>
<FONT color="green">089</FONT>                    return a.getName().compareTo(b.getName());<a name="line.89"></a>
<FONT color="green">090</FONT>                }<a name="line.90"></a>
<FONT color="green">091</FONT>            });<a name="line.91"></a>
<FONT color="green">092</FONT>            return ConstArray.array(contents);<a name="line.92"></a>
<FONT color="green">093</FONT>        }<a name="line.93"></a>
<FONT color="green">094</FONT>        <a name="line.94"></a>
<FONT color="green">095</FONT>        /**<a name="line.95"></a>
<FONT color="green">096</FONT>         * Gets the length of a file<a name="line.96"></a>
<FONT color="green">097</FONT>         * @param file  file to stat<a name="line.97"></a>
<FONT color="green">098</FONT>         * @return the length of the file in bytes<a name="line.98"></a>
<FONT color="green">099</FONT>         * @throws FileNotFoundException   &lt;code&gt;file&lt;/code&gt; not found<a name="line.99"></a>
<FONT color="green">100</FONT>         */<a name="line.100"></a>
<FONT color="green">101</FONT>        static public long length(final File file) <a name="line.101"></a>
<FONT color="green">102</FONT>                                            throws FileNotFoundException {<a name="line.102"></a>
<FONT color="green">103</FONT>            if (!file.isFile()) { <a name="line.103"></a>
<FONT color="green">104</FONT>                throw new FileNotFoundException();<a name="line.104"></a>
<FONT color="green">105</FONT>            }<a name="line.105"></a>
<FONT color="green">106</FONT>            return file.length();<a name="line.106"></a>
<FONT color="green">107</FONT>        }<a name="line.107"></a>
<FONT color="green">108</FONT>        <a name="line.108"></a>
<FONT color="green">109</FONT>        /**<a name="line.109"></a>
<FONT color="green">110</FONT>         * Opens an existing file for reading.<a name="line.110"></a>
<FONT color="green">111</FONT>         * @param file  file to open<a name="line.111"></a>
<FONT color="green">112</FONT>         * @return opened input stream<a name="line.112"></a>
<FONT color="green">113</FONT>         * @throws FileNotFoundException  &lt;code&gt;file&lt;/code&gt; not found<a name="line.113"></a>
<FONT color="green">114</FONT>         */<a name="line.114"></a>
<FONT color="green">115</FONT>        static public InputStream read(final File file) <a name="line.115"></a>
<FONT color="green">116</FONT>                                           throws FileNotFoundException {<a name="line.116"></a>
<FONT color="green">117</FONT>            if (!file.isFile()) { <a name="line.117"></a>
<FONT color="green">118</FONT>                throw new FileNotFoundException();<a name="line.118"></a>
<FONT color="green">119</FONT>            }<a name="line.119"></a>
<FONT color="green">120</FONT>            return new FileInputStream(file);<a name="line.120"></a>
<FONT color="green">121</FONT>        }<a name="line.121"></a>
<FONT color="green">122</FONT>        <a name="line.122"></a>
<FONT color="green">123</FONT>        /**<a name="line.123"></a>
<FONT color="green">124</FONT>         * Creates a file for writing.<a name="line.124"></a>
<FONT color="green">125</FONT>         * @param file  file to create<a name="line.125"></a>
<FONT color="green">126</FONT>         * @return opened output stream<a name="line.126"></a>
<FONT color="green">127</FONT>         * @throws IOException    &lt;code&gt;file&lt;/code&gt; could not be created<a name="line.127"></a>
<FONT color="green">128</FONT>         */<a name="line.128"></a>
<FONT color="green">129</FONT>        static public OutputStream writeNew(final File file) throws IOException {<a name="line.129"></a>
<FONT color="green">130</FONT>            if (!file.createNewFile()) {<a name="line.130"></a>
<FONT color="green">131</FONT>                throw new IOException();<a name="line.131"></a>
<FONT color="green">132</FONT>            }<a name="line.132"></a>
<FONT color="green">133</FONT>            return new FileOutputStream(file);<a name="line.133"></a>
<FONT color="green">134</FONT>        }<a name="line.134"></a>
<FONT color="green">135</FONT>    }<a name="line.135"></a>




























































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